Certain known types of foam producing devices, as disclosed for example in U.S. Pat. Nos. 4,147,306 and 4,156,505, employ a deformable reservoir of foamable fluid and air, discharge means, and foam producing means which include both a foam overlay or filter and a ball check valve. The foam producing means has some type of well with air passages which form a mixing chamber. When the reservoir is squeezed, the liquid and air are mixed in the chamber. The mixture is passed through the overlay to produce foam which is discharged through the orifice means. The check valve is disposed in the path of liquid flow, is opened by the squeezing action and is closed when the pressure is released. The valve when closed prevents downward flow or liquid or foam which otherwise could clog or jam the dispenser.
However, such known arrangements suffer from certain other disadvantages. For example when the device is turned upside down, the valve is opened and liquid can flow out of the device or can remain in the well whereby subsequent foam producing actions will not be satisfactory because the ratio of liquid to air in the mixing action is adversely affected.
In the present invention, these disadvantages are overcome by using a check valve disposed out of the path of liquid flow, the check valve being used to control the backward flow of air from outside the device into the the interior to recharge the air supply used in subsequent foam dispensing operations.